The art is replete with surgical stapling instruments used for applying parallel rows of staples through compressed living tissue. These types of stapling devices are used, for example, in transecting or reconnecting intestinal, gastric, skin and lung tissue.
One known surgical stapling instrument of this type is well known and is currently available under the trade designation "The ILA Stapler", catalog #3957 by Minnesota Mining and Manufacturing Company, St. Paul, Minn. The use of the stapler is described in the publication entitled "Surgical Stapling, Gastric and Small Bowel Procedures, Volume I", ISBN 0-937433-00-4, Library of Congress Catalog Number 85-082599 available from Minnesota Mining and Manufacturing Company, St. Paul, Minn. the contents of which are expressly incorporated herein by reference. The ILA Stapler and an improvement thereto is described in Redmond et al., U.S. Pat. No. 4,863,088 the entire specification of which is also herein expressly incorporated by reference. That stapling instrument comprises first and second elongate structural members each comprising a handle part and a jaw part projecting from a first end of the handle part. The structural members have pivot means at second ends of their handle parts adapted for free engagement and disengagement in a plane normal to the directions in which the members are elongate, which pivot means afford, when engaged, relative pivotal movement of the structural members in the plane between a closed position with the jaw parts in closely spaced relationship, and an open position spaced farther from each other than in the closed position. An elongate locking member having a pivot point closely adjacent a first end is mounted at its pivot point on the first end of the second structural member for pivotal movement around an axis generally normal to the plane between a locking position generally aligned with the handle part of the second structural member, and a release position with a second end of the locking member spaced from the second end of the second structural member. The first end of the locking member and the handle part of the first structural member adjacent its first end have surfaces adapted, when the pivot means are engaged and the structural members are in their open position, for engagement during movement of the locking member from its release position to its locking position to forcefully move the structural members to their closed position so that high compressive forces can be applied on tissues to be stapled between the jaw parts of the structural members. A means adapted for releasable engagement between the elongate locking member and the second structural member is provided for releasably holding the locking member in its locking position and thus maintain any compressive forces applied between the jaw parts. The stapling instrument is adapted to have a fixed or removable anvil positioned along one of the jaw parts, and a cartridge containing a plurality of staples disposed in rows positioned along the other of the jaw parts in opposition to the anvil, and the cartridge includes manually actuatable means for sequentially ejecting the staples from the cartridge to press the staples against the anvil to engage and close the staples in tissues between the jaw parts when the structural members are in their closed position. Additionally, if desired, the cartridge can include a knife that moves along and bridges between the cartridge and anvil to cut tissues between the rows of applied staples.
Typically the jaw parts of the ILA stapler are positioned adjacent the tissue to be stapled, if necessary the tissue is everted between the stapler jaw parts, the jaw parts are approximated adjacent the tissue to be stapled, and the stapler is clamped on the tissue by moving the jaw parts to the closed position. In some surgical procedures the clamping force results in tissue that is highly compressed to ensure, inter alia, proper hemostasis in the tissues being stapled. The clamping force is present in various degrees in each of the surgical procedures for an ILA type surgical stapler. Such a clamping force causes tissue trauma in the tissue to be stapled, at least to some degree.
The ILA stapler encounters problems because it is difficult to determine when a spent cartridge is loaded in the stapler. Typically a spent cartridge may be inadvertently left in a stapler after it has been fired during a surgical procedure where the stapler is used several times for the same patient. When the stapler is loaded with a spent cartridge and the stapler jaw parts are clamped on both sides of tissue to be stapled, the tissue is subject to the undesirable trauma resulting from the compressive forces created by the jaw parts and the user must disengage the jaw parts, replace the spent cartridge with an unused cartridge and again approximate the stapler adjacent the tissue to be stapled. These additional actions consume precious time during the surgical procedure.
One surgical stapler cartridge lockout device is described in U.S. Pat. No. 4,892,244 which illustrates means for preventing the firing means of a stapler from being fired when the stapler is loaded with a spent stapler cartridge. The use of such a lockout mechanism, however, does not prevent the jaw parts of the stapler from being clamped on the tissue to be stapled when the stapler is loaded with a spent cartridge.